We have found that cells propagated in vitro from CJD infected brain are transformed and able to produce monstrous tumors in nude mice. These cultures thus far have not yielded any detectable conventional viruses by a number of virological and EM studies. It is our aim to further establish and explore this novel biological property associated with unconventional infectious agents. To that end propagation of cultures from CJD infected brains at early and late stays will be undertaken and their in vitro, transplantation and virological studies will be pursued. Determination of CJD infectivity in such cultures will also be assessed. The second major part of this project deals with further purification of the CJD agent. Reproducible titration studies of subcellular fractions indicate 40-100% of infectivity can be isolated with the synaptosomal-mitochondrial subcellular fraction. Derivatives of this fraction will be used for titration and purification of agent relative to starting protein. Gel analysis of derivative extracts combined with specific isotopic and affinity labeling techniques will be used to uncover and trace CJD specific proteins.